package leetcode;

public class Leetcode110 {
    public boolean isBalanced(TreeNode root) {
        if(root==null){
            return true;
        }
        return isBalanced(root.left)&&isBalanced(root.right)&&Math.abs(height(root.left)-height(root.right))<=1;

    }
    public int height(TreeNode root){
        if(root==null){
            return 0;
        }
        return Math.max(height(root.left),height(root.right))+1;
    }

    public boolean isBalanced1(TreeNode root) {
        return recur(root) != -1;
    }

    private int recur(TreeNode root) {
        if (root == null) return 0;
        int left = recur(root.left);
        if(left == -1) return -1;
        int right = recur(root.right);
        if(right == -1) return -1;
        return Math.abs(left - right) < 2 ? Math.max(left, right) + 1 : -1;
    }


}
